An attendee inspects a P20 Pro smartphone, manufactured by Huawei Technologies Co., during its unveiling in Paris, France, on Tuesday, March 21, 2018.

The smartphone market is slowing, users are holding onto their devices for longer and some manufacturers are feeling the heat. The response from technology firms? Pack the next generation of handsets with crazy features.

Folding screens and an increased number of cameras are among some of the technologies touted to be part of upcoming devices from major firms this year and next.

China's Huawei, which is now the second-biggest smartphone maker in the world, will unveil a folding phone next year. Richard Yu, the CEO of Huawei's consumer division, announced the plans in an interview with German newspaper Die Welt earlier this week.

"Why are you still using a computer? Probably because the smartphone display is too small for you. We will change that. It is conceivable that a display can be folded out," Yu said, according to a translation.

Many companies are thinking about what then next generation of smartphones will look like. While Huawei has managed to grow rapidly, recently overtaking Apple as the world's second-largest smartphone maker, not all vendors have fared well. Smartphone shipments fell 1.8 percent year-on-year in the second quarter, according to IDC (International Data Corporation), with Samsung seeing a decline of over 10 percent.

The South Korean electronics giant is looking towards boosted features to help reverse that. In an exclusive interview with CNBC, DJ Koh, the CEO of Samsung's mobile division, said his company would unveil details of a foldable smartphone this year.

While many may perceive foldable phones to be a variant of a flip phone, the technology is very different. Flip phones relied on a hinge to connect two separate parts of the device. Foldable phones will actually see screens that are able to bend thanks to advances in display technology. The idea, as Yu said, is to increase the screen size of a device, but still allow a user to keep it in their pocket.

Folding screens could help smartphone makers attract more users bored of standard rectangular devices. But there are major barriers to adoption. One of those is price.

Neil Shah, research director at Counterpoint Research, said such devices released by the likes of Huawei and Samsung could cost $1,500 alongside other potential issues.

"The barriers to adoption would be the bulkiness of the phones to start with to achieve the goal of pocketability without a bulge. Secondly, bigger sharper displays will be power hungry, so battery backup in a folding form-factor will need rethinking and some additional design innovation," Shah told CNBC by email Friday.

More camera power

When Huawei launched the P20 Pro device earlier this year with a triple camera packing a collective 68-megapixels, it would have been easy to think that we've reached peak smartphone camera. But you'd have been wrong.

South Korean electronics maker LG sent invites out Thursday to its V40 ThinQ smartphone launch in October. The tagline says "Take 5," which could hint that the device will pack five cameras. Several rumors have suggested that LG's handset will have three cameras on the back and two on the front.

Chinese vendor Oppo also has a triple-camera device called the R17 Pro. Apple's latest iPhone XS Max flagship and the Samsung S9 Plus have a dual camera.

Packing smartphones with more cameras and other sensors is important for improved picture quality, but also for new experiences like augmented reality (AR) as demonstrated by Apple. And marketing the camera has always been a big move from manufacturers. This trend is set to continue.

"Multiple camera sensors configuration is going to be commonplace though marketing it well for right differentiated use-cases will make it stick and usually the likes of Apple, Samsung or Huawei are good at it," Shah said.